One of the major objectives will be isolation and characterization of the growth factor (PGF) produced by plerocercoid larvae of the tapeworm, Spirometra mansonoides. Procedures for initial steps of purification have been established and when final purification is accomplished, characterization studies will begin. Steps have been taken to increase the numbers of plerocercoids available so that preparative fractionation procedures may be undertaken. When purified PGF is obtained in sufficient quantities, studies to determine the direct effects of this factor will be undertaken. An additional objective will be to determine the effects of PGF in hypophysectomized monkeys in acute as well as chronic studies. If PGF is biologically active in monkeys, it is conceivable that it will be active in humans, A further objective will be to continue to examine the effects of PGF on metabolism of laboratory rodents and how these effects relate to other growth factors, such as growth hormone, somatomedin, and insulin. More specifically it is planned to examine in detail the differences in the effects of PGF and growth hormone on lipid metabolism. The effects of PGF and GH on the activities of key enzymes of lipid metabolism will be determined in intact hamsters. In addition, the effect of PGF on growth and development of the thymus of hamsters will be examined.